Conventional optical systems are constructed by arranging optical components such as prisms, lenses, mirrors, LDs, and/or CCDs in predetermined positions. In such optical systems, since the relative positions and angles between the optical components are required to be accurate to align the optical axes thereof, specialized jigs and positioning mechanisms, etc., are used for positioning. Also, there is already known an optical system composed of prisms in which the prisms each provided with a fitting pin are coupled to each other for positioning (refer to Patent Document 1, for example).
Patent Document 1: Japanese Patent No. 3134850